HarmonyOS 鸿蒙Next 如何查看在线和本地的word、excel等文件

目前可以实现预览的文件后缀是；pdf、doc、docx、xls、xlsx、ppt、pptx

可参考以下demo：

import common from '[@ohos](/user/ohos).app.ability.common';
import fs from '[@ohos](/user/ohos).file.fs';
import { filePreview } from '[@kit](/user/kit).PreviewKit';
import { BusinessError } from '[@kit](/user/kit).BasicServicesKit';
import fileUri from '[@ohos](/user/ohos).file.fileuri';
let context = getContext(this) as common.UIAbilityContext;
let uiContext = getContext(this);


let fileInfo: filePreview.PreviewInfo = {
 // 文件预览信息，包含了文件标题名、uri以及文件类型（mimeType）
 title: '1.xls',
 // title: '蓝牙ble 模式的demo使用说明1.pdf',
 // uri: 'file://com.lvhui.myapplication/data/storage/el2/base/haps/entry/files/蓝牙ble 模式的demo使用说明1.pdf',
 uri: 'file://com.lvhui.myapplication/data/storage/el2/base/haps/entry/files/1.xls',
 // mimeType: 'application/pdf' // 文件(夹)的媒体资源类型，如text/plain
 mimeType: 'application/vnd.ms-excel' // 文件(夹)的媒体资源类型，如text/plain
};

function copyFile() {
 console.log("copyFile!")
 // let srcFileDescriptor = context.resourceManager.getRawFdSync('蓝牙ble 模式的demo使用说明1.pdf');
 let srcFileDescriptor = context.resourceManager.getRawFdSync('1.xls');
 //这里填rawfile文件夹下的文件名（包括后缀）
 let stat = fs.statSync(srcFileDescriptor.fd)
 console.log(`stat isFile:${stat.isFile()}`);
 // 通过UIAbilityContext获取沙箱地址filesDir，以Stage模型为例
 let pathDir = context.filesDir;
 console.log("path:", pathDir)
 // let dstPath = pathDir + "/蓝牙ble 模式的demo使用说明1.pdf";
 let dstPath = pathDir + "/1.xls";
 let dest = fs.openSync(dstPath, fs.OpenMode.CREATE | fs.OpenMode.READ_WRITE)
 let bufsize = 4096
 let buf = new ArrayBuffer(bufsize)
 let off = 0, len = 0, readedLen = 0
 while (len = fs.readSync(srcFileDescriptor.fd, buf, { offset: srcFileDescriptor.offset + off, length: bufsize })) {
   readedLen += len

   fs.writeSync(dest.fd, buf, { offset: off, length: len })
   off = off + len
   if ((srcFileDescriptor.length - readedLen) < bufsize) {
     bufsize = srcFileDescriptor.length - readedLen
   }
 }
 fs.close(dest.fd)
}


[@Entry](/user/Entry)
[@Component](/user/Component)
struct Index {
 [@State](/user/State) message: string = '预览文件';


 build() {
   Row() {
     Column() {
       Button('传到沙箱')
         .onClick(()=>{
           copyFile()
         })

       Button(this.message)
         .fontSize(50)
         .fontWeight(FontWeight.Bold)
         .onClick(() => {
           filePreview.openPreview(uiContext, fileInfo).then(() => {
             console.info('openPreview success');
           }).catch((err: BusinessError) => {
             console.error('openPreview failed, err = ' + err.message);
           });
         })
     }
     .width('100%')
   }
   .height('100%')
 }
}